Electrical switch having quick break wiping contacts



L. B. RONK july 21, 1964 ELECTRICAL SWITCH HAVING QUICK BREAK WIPING CONTACTS Filed April 4, 1962 2 Sheets-Sheet 1 L. B. RQNK July 21, 1964 ELECTRICAL SWITCH HAVING QUICK BREAK WIPING CONTACTS 2 Sheets-Sheet 2 Filed April 4, 1962 United States Patent This invention relates to electrical switches, and with regard to certain more specific features, to manually operable, air-break, disconnect switches.

Among the several objects of the invention may be noted the provision of a manually operable, air-break, disconnect switch for substantial currents adapted primarily, but without limitation, for use in entrance service connections to rural customers premises from power lines, and preferably to be used on the customers side of the meter generally employed; the provision of a switch of the class described which at low cost is adapted to take the place of the usual more costly circuit breaker used for the purpose; the provision of a switch of the class described having improved wiping, quick-break, low-arcing, high-pressure contacts; and the provision of a switch of the class described which is of safe and rugged construction designed for effective use over long period of time, and one which is easily operable by hand. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the constructions hereinafter described, and the scope of which will be indicated in the following claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

FIG. 1 is a side elevation showing the switch in open position and mounted according to one mode in a switch housing which is sectioned;

FIG. 2 is a fragmentary vertical section of the switch in closed position and mounted in a housing according to another mode, the view of the switch elements per se being taken on line 2-2 of FIG. 3;

FIG. 3 is a front view of the switch per se removed from its box, being viewed on line 33 of FIG. 2;

FIG. 4 is a horizontal section taken on line 44 of FIG. 3;

FIG. 5 is a rear view of the switch per se being viewed on line 5-5 of FIG. 1;

FIG. 6 is a vertical section taken on line 66 of FIG. 2; and

FIG. 7 is an enlarged detail section taken on line 77 of FIG. 6.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Service entrance connections to some customers of electricity drawn from power lines carry substantial currents such as, for example but without limitation, to farm owners supplied with current by the Rural Electrification Administration. Currents drawn at 100 amps. at 120-220 volts are not uncommon. Disconnect switches for such service entrances are usually located on the customers side of the meter. In order to provide a customer with a disconnect switch, it has heretofore been the practice to employ a costly and usually troublesome circuit breaker. By means of the present invention there is provided a safe, quick-break manually operable disconnect switch which at low'cost is' constructed for trouble-free long life even in detrimental environments. The environment of switches to which the invention applies is a meter pole which carries the customers service connections, including his meter. The switch of the present invention is preferably mounted in a box carried on the pole and connected after the meter.

Referring now more particularly to the drawings, numeral 1 indicates a switch base composed of a suitable block of insulating material on opposite sides of which are attached U-shaped resilient switch blades 3, composed for example of Phosphor bronze. Each blade 3 has a comparatively short free leg 5 and a comparatively long anchored leg 7. Attachment to the base 1 is made by screw connections 9, leaving the shorter legs 5 for springing or resilient action centered more or less at a loop 11 formed between the short and long legs 5 and 7. Riveted to each short leg at its outer end is a heavy-duty contact 13 composed of suitable materials adapted best to resist arc erosion, such as for example copper faced with coin silver. Each longer leg 7 extends beyond the base 1, as shown at 15, to provide terminal portions in which are screws 17.

At numerals 19 are shown another pair of resilient switch blades fastened to the base 1 by means of screw fasteners 21. The blades 19 are of general S-shape having short anchored end portions 23 at which said connections 21 are made with the base. The blades 19 have comparatively long free end portions 25 having connections 27 with the fixed portions 23. The free portions 25 overlie the blades 3. The ends 23 extend to form terminals 24 in which are screws 26. The fixed portions 23 are joined with the connections 27 by means of bends 22, which form approximate centers of rotation for the overlying portions 25 respectively. The blades 19, like blades 3, are also conductive and springy or resilient. The por tions 25 carry heavy-duty contacts 14, like the contacts 13.

The long overlying end portions 25 of the blades 19 are fastened together by an insulator block 29. Fastening rivets are shown at 31. A metal button or latch 33 is staked in the plate 29 at a location between and insulated from the contacts 14. As will appear, this button is part of a camming and latching arrangement for switch operation to be described. Above button 33 is located a notch 35 in the upper margin of the insulating plate 29. This notch accommodates and aligns a switch-operating latch lever 37. This lever 37 is of general L-shape, one leg 43 of which terminates in an operating extension 39. As will appear, leg 43 also acts as a wedge cam. In it is a central round socket 44. The other leg 41 is terminated by a pair of bent spaced hooks 45 which loop around the sides of a T-head 47, branching at 49 from an eye piece 51. A screw 53 attaches the eye piece 51 to the upper end of the base 1. This screw also holds one end of a clamp bar 55, being threaded therein. A second and similar screw 57, passing through the hole near the lower margin of base 1, is threaded into the other end of the clamp bar 55.

Slidable under the clamp bar 55 (when loose) are two adjustable supporting leg pieces 59, slotted as shown at 61 to accommodate the screws 53 and 57. These pieces 59, which have oifset support pads 63, may be adjustably positioned on the back of the base 1 before the screws 53 and 57 are tightened. As shown in FIG. 1, the pieces 59 are supported in connection with support parts 65 and 67 carried on the back 71 of a switch box B; or they may be attached directly to the back 73 of a switch box C, as shown in FIG. 2. In the latter case a hook support 75 and screw 77 are employed. The pads 63 are provided with suitable openings for cooperating with either of the supports described, but these require no further description, being conventional.

It will be clear from FIG. 7 that the screw 53 performs a double function of drawing up the clamping plate 55 and holding in position the eye 51. The latter provides the lower pivot for the lever 37. The notch 35 in the insulating plate 29 provides means by which the part 41 of the lever 37 may reach a position nearly perpendicular to the base 1 when recess 44 engages head 33. The head 33 is located as nearly over the pivot point of lever 37 at 47 as is practicable, so that the reaction between parts 44 and 33 does not have sufficient operating moment on lever 37 to drive it to open position. Opening can thus be initiated only by manually pushing up the end part 39 of lever 37.

At numeral 99 is shown an adjustable release screw threaded into the plate 29 under part 43 of the lever 37. By adjusting this screw so that it will slightly spring out the part 43, release action between the latching parts 44 and 33 may be made sufficiently sensitive so that a slight touch of the finger on the operating end 39 will cause switch opening.

The terminals 15 and 24 are adapted to receive any one of various types of wire connectors, such as illustrated, for example, at numerals 81, being held by screws 17 or% as the case may be. These connectors attach incoming line wires 85 from the meter and outgoing wires 83 to the customers line. Set screws 87, threaded into the connectors 81, hold the lugs and wires in place. Other types of wire connections may be used.

In FIG. 1, the type of mounting in box B is shown. Such a box may be of the type having an access opening 89 surrounded by a water-deflecting channel 91 and covered by a conventional openable door 93. Within the opening 89 is attached a plate 95, slotted as at 97. The slot 97 is slightly wider than the lever 37 and accommodates vertical swinging movement thereof. The boX C of FIG. 2 may be likewise equipped.

An open position of switch parts per se is shown in FIG. 1 and a closed position thereof in FIG. 2. In the open position, the lever 37 is up. The unsprung position of the switch blades 19 and that of the switch blades 3 is such that the contacts 13 and 14 are separated. To close the switch, the lever 37 is rotated down by applying a finger on its operating extension 39. This causes the leg 43 of the lever 37 to engage the button 33, functioning therewith as a wedge or cam. As the lever 37 moves clockwise the insulating plate 29 is swung anticlockwise, which brings together the contacts 13 and 14. At the end of the closing action the button 33 drops into the recess 44, as shown in FIG. 2. The switch thereafter remains closed with the switch blades 3 and 19 tensioned so as to obtain a constant pressure between contacts 13 and 14. While this tends to reopen the switch, reopening cannot automatically occur, because the pressure between button 33 and the recess 44 applies little or no opening moment on lever 37 around the center at 47, as above made clear.

To open the switch, the lever 37 is swung anti-clockwise by applying light pressure under the. part 39. This opens the latch constituted by parts 33 and 44, whereupon the blade parts and 25 rapidly rotate clockwise and quickly separate the contacts. Once the latch 33, 44 has released, no further pressure is required on the member 39 for opening action, since the sliding movement of the part 33 on the part 44 of the lever 37 moves the latter up.

Opening movement of the plate 29 is limited by contact of the lower end of the same with the plate 95. Such contact may occur during initial opening of the switch due to inertial effect, as is illustrated in FIG. 1. When plate 29 comes to rest, contact between it and the plate 95 is maintained only if plate 95 is within range of the springing movement; otherwise not. In any event, when the switch is open the lever 37 is free of any tension and does not of itself restrict the movement of plate 29 when the switch is open.

A feature of importance is that the approximate center of rotation of the contacts 13 during switch-opening and -closing movements is in the region of the loop 11; whereas the approximate center of rotation of the contacts 14 on blades 19 is at the bend 22 between blade parts 27 and 23. As a result, the contacts 13 and 14 incur a transverse sliding action between their faces as switch-opening and -closing movements occur. Such action has the effect of removing any oxidation products and the like that occur due to weathering, or such as may be produced by any small amount of arcing as may occur.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An electrical switch comprising an insulating base, a first spaced pair of U-shaped resilient switch blades, one leg of each of which is attached to the base and the other leg of each of which is resiliently movable and carries a contact, the legs of each blade being connected by a loop forming an approximate center about which its respective contact is movable, a second spaced pair of resiilent S-shaped switch blades each connected at one end to the base adjacent one of said loops and having its other end overlying a U-shaped blade, said second pair of blades carrying a second pair of contacts, the connections of the second blades with the base forming approximate centers about which their contacts are movable respectively, an insulating plate connecting the second pair of switch blades, an L-shaped operating lever having one leg pivoted to the base for rotation in a plane between the first pair of switch blades, the other leg of the operating lever forming operating cam and catch parts and a latch part on the insulating plate between the second pair of blades adapted to be engaged by said cam and catch parts on the lever for closing the contacts and tensioning the blades upon rotation of said lever.

2. An electrical switch comprising an insulating base, a first pair of U-shaped resilient switch blades each of which has first legs affixed to the base and a second overlying free leg, the legs of each blade being connected by a loop, a contact at the end of each free leg, a second pair of parallel S-shaped resilient switch blades each of which has one end portion afiixed to the base adjacent one of said loops, the other end portion of each of said second pair of blades being free and overlying a free leg of one of the first pair of blades respectively, a contact at the end of the free leg of each S-shaped blade adapted to engage a contact on a U-shaped blade, an insulating plate connecting the free portions of the S-shaped blades, an L-shaped operating and latch member, a pivot member swingably attaching one leg of the operating member to the base in a plane located between the fixed legs of the first pair of blades, said operating member having a second leg adapted for engagement with the part on said insulating plate which lies in a plane between the free ends of the S-shaped blades, said second leg of the operatmg member adapted for a camming engagement with said part on said insulating plate adapted to force the free legs of the second pair of blades into springing engagement with the free legs of the first pair of blades.

3. An electrical switch according to claim 2, including latch means between the insulating plate and said operatmg rtnember adapted to maintain said springing engagemen 4. An electrical switch according to claim 2, including adjustable support means on said base, a clamping member therefor, and means adapted to hold said clamping member comprising a holding screw for said pivot member and said clamping member.

5. An electrical switch comprising an insulating base, a first resilient switch blade one end of which is attached to said base and the other end of which is free and carries a first contact movable over one path, a second resilient switch blade, one end of said second blade being 5 attached to the base and the other end being free and carrying a second contact normally disengaged from said first contact, said second contact being movable over another path to effect sliding engagement with the first contact, a generally L-shaped operating lever having first and second legs, inner ends of which legs are connected to form an angle portion, an outer end of the first leg being pivoted to the base, an outer end of the second leg having means for manual operation of the lever, a catch on the second leg near said angle portion, said second leg having a camming portion located between said catch and 1 the outer end operating means, and a latch connected to and movable with said second blade, said latch adapted to be engaged first by said camming portion for driving the contacts into engagement upon rotation of the lever, and then for engagement by the catch to maintain con- 5 tact engagement.

References Cited in the file of this patent UNITED STATES PATENTS Knowlton Mar. 7, 1950 

1. AN ELECTRICAL SWITCH COMPRISING AN INSULATING BASE, A FIRST SPACED PAIR OF U-SHAPED RESILIENT SWITCH BLADES, ONE LEG OF EACH OF WHICH IS ATTACHED TO THE BASE AND THE OTHER LEG OF EACH OF WHICH RESILIENTLY MOVABLE AND CARRIES A CONTACT, THE LEG OF EACH BLADE BEING CONNECTED BY A LOOP FORMING AN APPROXIMATE CENTER ABOUT WHICH ITS RESPECTIVE CONTACT IS MOVABLE, A SECOND SPACED PAIR OF RESIILENT S-SHAPED SWITCH BLADES EACH CONNECTED AT ONE END OF THE BASE ADJACENT ONE OF SAID LOOPS AND HAVING ITS OTHER END OVERLYING A U-SHAPED BLADE, SAID SECOND PAIR OF BLADES CARRYING A SECOND PAIR OF CONTACTS, THE CONNECTIONS OF THE SECOND BLADES WITH THE BASE FORMING APPROXIMATE CENTERS ABOUT WHICH THEIR CONTACTS ARE MOVABLE RESPECTIVELY, AN INSULATING PLATE CONNECTING THE SECOND PAIR OF SWITCH BLADES, AN L-SHAPED OPERATING LEVER HAVING ONE LEG PIVOTED THE BASE FOR ROTATION IN A PLANE BETWEEN THE FIRST PAIR OF SWITCH BLADES, THE OTHER LEG OF THE OPERATING LEVER FORMING OPERATING CAM AND CATCH PARTS AND A LATCH PART ON THE INSULATING PLATE BETWEEN THE SECOND PAIR OF BLADES ADAPTED TO BE ENGAGED BY SAID CAM AND CATCH PARTS ON THE LEVER FOR CLOSING THE CONTACTS AND TENSIONING THE BLADES UPON ROTATION OF SAID LEVER. 